Phosphorus pyridine compound

ABSTRACT

An agent for enhancing the drug effects of an antitumor drug, which comprises a compound of the formula I: ##STR1##  or a pharmaceutically acceptable salt of the compound.

This is a Division of application Ser. No. 07/865,489 filed on Apr. 9,1992 which is a Division of 07/729,904 filed Jul. 15, 1991 (U.S. Pat.No. 5,130,303), which is a Continuation of 07/386,254 filed Jul. 28,1989 (Abandoned).

The present invention relates to an agent for enhancing the drug effectsof an antitumor drug, which comprises a pyridine derivative or apharmaceutically acceptable salt thereof, as an active ingredient.

Remarkable developments have been observed in the chemotherapy ofcancer. There have been an increasing number of cases in which some ofcancers have been reportedly completely healed. However, there are stilla number of problems yet to be solved. Among them, to reduce the sideeffects, to overcome drug resistance against antitumor drugs and toprevent relapse and metastatis are problems which are desired to besolved as soon as possible. Further, no antitumor drugs have beendeveloped which are truly effective against solid cancers such ascarcinoma of the colon, cancer of the stomach and carcinoma of theesophagus.

In the clinical field, it is frequently experienced that antitumor drugswhich were initially effective, tend to be non-effective during anextended period of treatment. Further, when a tumor metastasizes orrecurs, an antitumor agent is no longer effective in many cases.

Among various factors attributable to such tendency, it is known to bean important factor that cancer cells acquire drug resistance againstantitumor drugs.

Yet, it frequently happens that cancer cells which acquired drugresistance against a certain particular antitumor drug, also showresistance against many other antitumor drugs which are totallydifferent from the particular antitumor drug in their chemicalstructures or functional mechanisms (multidrug resistance), whichconstitutes a serious obstacle in the chemotherapy of cancer.

The study on the multidrug resistance against antitumor drugs has beenrapidly progressed in recent years, and a part of the mechanism has beenmade clear. Namely, in the cancer cells which acquire resistance, anincrease of a certain P-glycoprotein is observed which has a function ofa drug efflux pump, whereby the antitumor drug is pumped out of thecells in an energy dependent fashion, and consequently, theconcentration of the antitumor agent in the cells decreases.

Tsuruo et al have found that Verapamil i.e. one of calcium antagonisticdrugs overcomes the multidrug resistance against antitumor drugs (seeCancer Res. 41; 1967-1972 (1981)).

Akasawa et al have reported that calcium antagonistic drug nicardipinenhances the antitumor activities of vindecine sulfate (Cancer andChemotherapy, vol. 11, 943-947 (1984)). It has also been reported thatcalcium antagonistic drug diltiazem enhances the drug effects ofvincristine (VCR) (see Japanese Unexamined Patent Publication No.208222/1983).

These three drugs are all calcium antagonistic substances, but they haveno structural similarity at all. Further, it is known that there is norelationship between the strength of the calcium antagonistic effectsand the strength of the effects for enhancing the drug effects of theantitumor drugs.

Further, certain dihydropyridine compounds are known to increase thesensitivity of cancer cells to carcinostatic drugs (see JapaneseUnexamined Patent Publication No. 135381/1988) or to be effective forpreventing metastatis of cancer (Japanese Unexamined Patent PublicationNo. 87516/1987).

It has already been known that 1,4-dihydropyridines among the compoundsof the present invention have strong vasodilator activities by calciumantagonism, and they are useful as pharmaceuticals effective againsthypertension, angina pectoris or disorder of cerebral circulation (U.S.Pat. Nos. 3,485,847, 3,644,627, 3,985,758 and 4,576,934).

On the other hand, substantially nothing has been known with respect tothe biological activities of the pyridines of the present invention.

The present inventors have found surprisingly that the compounds of theformula I as defined hereinafter and their pharmaceutically acceptablesalts are effective not only to suppress or diminish the drug resistanceagainst cancer cells which acquired the drug resistance againstantitumor drugs, but also to enhance the drug effects of antitumor drugsagainst cancer cells having no resistance. The present invention hasbeen accomplished on the basis of this discovery.

The present invention provides an agent for enhancing the drug effectsof an antitumor drug, which comprises a compound of the formula I:##STR2## wherein Ar¹ is phenyl, pyridyl, furyl or2,1,3-benzooxadiazol-4-yl, which may be substituted by one or twosubstituents selected from the group consisting of NO₂, CF₃, Br, Cl, F,R⁶ (wherein R⁶ is C₁ -C₄ alkyl), OH, OR⁶, OCHF₂, COOR⁶, NH₂, NHR⁶, NR⁶R⁷ (wherein R⁷ has the same meaning as R⁶) CONH₂ CONHR⁶, CONR⁶ R⁷,COSR⁶, SR⁶, S(O)R⁶, S(O)₂ R⁶, SO₃ H, SO₃ R⁶, SO₂ NH₂, SO₂ NHR⁶, SO₂ NR⁶R⁷, CN and phenyloxy;

the nitrogen-containing hereto ring portion represents a1,4-dihydropyridine ring or a pyridine ring;

Z is a group of the formula II: ##STR3## wherein each of R⁴ and R⁵ whichmay be the same or different is OH, C₁ -C₁₂ linear or branched primaryor secondary alkyloxy, C₃ -C₆ linear or branched unsaturated alkyloxy,C₃ -C₆ cycloalkyloxy, C₁ -C₆ alkoxy substituted by C₃ -C₆ cycloalkyl,OAr² (wherein Ar² is phenyl which may be substituted by halogen, C₁ -C₃alkyl or C₁ -C₃ alkoxy), OANR⁶ R⁷ (wherein A is C₂ -C₆ alkylene whichmay be substituted by C₁ -C₃ alkyl or Ar²), OAN(CH₂ Ar²)R⁶, OAOR⁶, OACN,NH₂, NHR⁶, NR⁶ R⁷, 1-piperidinyl or 1-yrrolidinyl, or R⁴ and R⁵ togetherform OYO (wherein Y is C₂ -C₄ linear saturated or unsaturated alkylenewhich may be substituted by R⁶, CO₂ R⁶, OR⁶ or A), NHYO, R.sup. 6 NYONHYNH, R⁶ NYNH or R⁶ NYNR⁷, or Z is CO₂ R⁸ (wherein R⁸ has the samemeaning as R³ defined hereinafter);

R¹ is present only when the nitrogen-containing hetero ring is a1,4-dihydropyridine ring, and it is R⁶, ANR⁶ R⁷, AN(CH₂ CH₂)₂ O, AOR⁶ orCH₂ phenyl;

R² is R⁶, Ar², Ar² CH=CH, Ar² CH(OH)CH₂, CHO, CN, CH₂ OH, CH₂ R⁶, CH₂,CH₂ N(CH₂ CH₂)₂ NR⁶, NH₂, NHR⁶ or NR⁶ R⁷ ;

R³ is hydrogen, C₁ -C₁₂ linear or branched alkyl, C₃ -C₆ linear orbranched unsaturated alkyl, C₃ -C₆ cycloalkyl, C₁ -C₆ alkyl substitutedby C₃ -C₆ cycloalkyl, AOR⁶, AO(CH₂)_(m) Ar² (wherein m is an integer offrom 0 to 3), (CH₂)_(m) Ar², ANH₂, ANHR⁶, ANR⁶ R⁷, ANR⁶ (CH₂)_(m) Ar²,AN{(CH₂)_(m) Ar² }{(CH₂)_(n) Ar³ } (wherein n has the same meaning as m,and Ar³ has the same meaning as Ar²), 1-benzyl-4-piperidinyl,1-benzyl-2-piperidinyl, 2-pyridinylmethyl, 3-pyridinylmethyl, AQ(wherein Q is pyr-rolidine or piperidine which may be substituted by(CH₂)_(m) Ar²), 4-R⁶ -1-piperazinyl, 4-Ar² -1-piperazinyl, 4-(Ar²)₂CH-1-piperazinyl or 4-(Ar²)₂ CH-1-(1,4-diazacycloheptyl);

or a pharmaceutically acceptable salt of the compound.

In this specification, "the compound of the present invention" refersgenerally to not only the compound of the formula I but also to thepharmaceutically acceptable salt thereof.

Now, the various substituents in the formula I for the compound of thepresent invention will be described specifically.

R¹ includes, for example, methyl, ethyl, methoxymethyl, methoxyethyl,aminoethyl, dimethylaminoethyl and benzyl.

R² includes, for example, methyl, phenyl, styryl, cyano, amino,methylamino, dimethylamino and hydroxymethyl.

R³ includes, for example, hydrogen, methyl, ethyl, n- and i-propyl, n-,i- and sec-butyl, n-pentyl, n-hexyl, n-octyl, n-decyl, cyclopropyl,cyclopentyl, cyclohexyl, cyclopropylmethyl, cyclopropylethyl,cyclohexylmethyl, cyclohexylethyl, allyl, 1-methylallyl, 2-methylallyl,3-methylallyl, 2-propynyl, 3-butynyl, phenyl, p-chlorophenyl,p-methoxyphenyl, benzyl, p-chlorobenzyl, p-methoxybenzyl, phenethyl,p-chlorophenethyl, p-methoxyphenethyl, methoxyethyl, ethoxyethyl,i-propoxyethyl, dimethylaminoethyl, benzylmethylaminopropyl,benzyloxyethyl, n-propoxyethyl, cyanoethyl, methylaminoethyl,aminoethyl, benzylmethylaminoethyl, benzylphenylaminoethyl,1-benzylpyridino-4-yl, 1-benzylpiperidino-2-yl, 2-pyridinomethyl,4-diphenylmethyl-1-piperadinoethyl, 4-methyl-1-piperadinoethyl,4-phenyl-1-piperadinoethyl, 2-oxopropyl and methylthioethyl.

Each of R⁴ and R⁵ includes, for example, hydroxy, methoxy, ethoxy, n-and i-propoxy, n-, i- and sec-butoxy, n-pentyloxy, n-hexyloxy,n-octyloxy, n-decyloxy, cyclopropyloxy, cyclopentyloxy, cyclohexyloxy,cyclopropylmethyloxY, cyclopropylethyloxy, cyclohexylmethyloxY,cyclohexylethyloxY, allyloxy, 1-methylallyloxy, 2-methylallyloxy,3-methylallyloxy, 2-propynoxy, 3-butynoxy, phenyloxy, p-chlorophenyloxy,p-methoxyphenyloxy, benzyloxy, p-chlorobenzyloxy, p-methoxybenzyloxy,phenethyloxy, p-chlorophenethyloxy, p-methoxyphenethyloxy,methoxyethyloxy, ethoxyethyloxy, i-propoxyethyloxy,dimethylaminoethyloxy, benzylmethylaminopropyloxy, benzyloxyethyloxy,n-propoxyethyloxy, cyanoethyloxy, amino, methylamino, dimethylamino,diisopropylamino, 1-piperidinyl and 1-pyrrolidinyl.

The case where R⁴ and R⁵ together form a ring includes, for example,1,2-dimethylethylenedioxy, 1,3-propylenedioxy,2,2-dimethyl-1,3-propylenedioxy, dimethyl-1,3-propylenedioxy,2,2-diethyl-1,3-propylenedioxy, 2-ethyl 1,3-propylenedioxy,2-isopropyl-1,3-propylenedioxy, 2-cyclobutyl-1,3-propylenedioxy,2-cyclohexyl-1,3-propylenedioxy, 2,2-diethoxy-1,3-propylenedioxy,1,1,3,3-tetramethyl-1,3-propylenedioxy, 1,4-dimethyl-l,4-butylenedioxy,2-dihydro-1,4-butylenedioxy, N-methyl-1,3-dimethylpropyleneaminooxy,N-methyl-1-methylethyleneaminooxy, N,N'-dimethylethylenediamino andN,N'-diethylethylenediamino.

Ar¹ includes, for example, phenyl, nitrophenyl, chlorophenyl,fluorophenyl, trifluoromethylphenyl, hydroxyphenyl, methoxyphenyl,methoxycarbonylphenyl, aminophenyl, methylaminophenyl,dimethylaminophenyl, aminocarbonylphenyl, methylaminocarbonylphenyl,dimethylaminocarbonylphenyl, methylphenyl, methylthiocarbonylphenyl,methylthiophenyl, methylsulfonylphenyl, sulfonylphenyl,methoxysulfonylphenyl, aminosulfonylphenyl, methylaminosulfonylphenyl,dimethylaminosulfonylphenyl and o-, m- and p-substituted cyanophenyl,2,3-dichlorophenyl and 2,1,3-benzooxadiazol-4-yl.

Among the compounds of the present invention, those of the formula Iwherein either one of substituents R¹, R², R³, R⁴ and R⁵ contains atleast one basic nitrogen atom capable of forming a salt, orpharmaceutically acceptable salts thereof are preferred, since theypresent preferred drug effect-enhancing agents for antitumor drugs.

Among the compounds of the present invention, those wherein thenitrogen-containing hetero ring is a 1,4-dihydropyridine ring, arecovered by the following Japanese Unexamined Patent Publications and canbe prepared in accordance with the method disclosed in thesepublications.

Japanese Unexamined Patent Publications No. 161392/1984, No. 69089/1985,No. 248693/1985, No. 258194/1985, No. 27995/1986, No. 30591/1986, No.37793/1986, No. 63688/1986, No. 63689/1986, No. 10092/1986, No.254596/1986, No. 257995/1986, No. 169795/1987, No. 195392/1987, No.68591/1988, No. 115889/1988, No. 115890/1988 and No. 115891/1988.

Among the compounds of the present invention, those wherein thenitrogen-containing hetero ring is a pyridine ring, include newcompounds. However, such compounds may readily be obtained by treatingthe corresponding 1,4-dihydropyridine derivatives with an oxidizingagent such as nitric acid, nitrous acid or chromic acid.

As described hereinafter, the compounds of the present invention enhancethe drug effects of antitumor drugs not only against cancer cells whichacquired drug resistance but also against cancer cells having no drugresistance. Therefore, they provide excellent advantages such that thedose of antitumor drugs to patients can be reduced, and toxicity or sideeffects can be reduced. Further, cross resistance can be overcome, whichprovides an important advantage that the number of useful antitumordrugs increases so that antitumor drugs can be selected to meet thesymptoms and conditions of the patients. Recurrence of cancer is one ofserious problems in the clinical field of chemotherapy of cancer. Inmany cases, this is regarded as a state where slightly remained drugresistant tumor cells have again proliferated.

The compounds of the present invention are capable of diminishing drugresistance when used in combination with antitumor agents, and they thuscan be used to prevent recurrence by killing all the tumor cells andcompletely healing the tumor. Further, the compounds of the presentinvention may be employed to prevent metastatis. The enhancement of thedrug effects of antitumor drugs by the combined use of the compounds ofthe present invention and the antitumor agents is expected also againstsolid cancer such as lung cancer, liver cancer or carcinoma of the colonto which the conventional antitumor agents used to be hardly effectivedue to formation of multidrug resistant gene (see Fojo et al, CancerRes., 45,3002-3007 (1986)).

The compounds of the present invention can be administered orally (inthe form of tablets, pills, powders, capsules, granules, etc.) orparenteral (in the form of injection drugs, intravenous drip infusiondrugs, suppositories, etc.). Further, compounds of the present inventionmay be administered alone or in admixture with antitumor drugs.

The dose of the compound of the present invention varies depending uponthe manner of administration, the age of the patient, the type ofdisease, the diseased condition and the type of concurrently usedantitumor agents. However, the dose is usually from 0.01 to 3 g,preferably from 0.05 to 1 g, per day for an adult. There is noparticular restriction as to the concurrently used antitumor drugs.However, vina alkaloids represented by vincristine and vinblastine,adriamycin, actinomycin-D, daunomycin and colchicine may be mentioned aspreferred examples.

These antitumor agents may be administered in such a dose and in such adosage form as usually employed clinically, and they may be administeredsimultaneously with the compound of the present invention, or before orafter the administration of the compound of the present invention.Various formulations may be employed for the oral administration of theactive component of the present invention. For example, the activecomponent may be formulated into tablets, granules, fine particles,powders, syrups or elixirs. Granules and powders may be filled incapsules to obtain unit dosage formulations, as the case requires.

Among such drug formulations for oral administration, solid drugs maycontain an excipient such as silicic anhydride, metasilicic acid,magnesium aluminate, synthetic aluminum silicate, lactose, sucrose, cornstarch, fine crystalline cellulose or hydroxypropyl starch, a bindersuch as gum arabic, gelatin, tragacanth, hydroxypropyl cellulose orpolyvinyl pyrrolidone, a lubricant such as magnesium stearate, talc orsilica, a disintegrator such as potato starch or calcium carboxymethylcellulose, or a wetting agent such as polyethylene glycol, sorbitanmonooleate, polyoxyethylene hardened caster oil or sodium laurylsulfate.

Tablets may be coated in accordance with a conventional method.

Among the drugs for oral administration, liquid formulations may be inthe form of aqueous or oily emulsions or syrups, or may be formulated ina dry product which is capable of being dissolved with a suitablevehicle prior to its use. Such liquid formulations may contain commonlyemployed additives, for example, an assisting agent for emulsificationsuch as sorbit syrup, methyl cellulose, gelatin or hydroxyethylcellulose, an emulsifier such as lecithin sorbitan monooleate orpolyoxyethylene hardened caster oil, a non-aqueous vihicle such as afractionated coconut oil, almond oil or peanut oil, or an antisepticsuch as methyl p-hydroxybenzoate, propyl p-hydroxybenzoate or sorbicacid.

These drugs for oral administration may further contain a preservativeor a stabilizer, as the case requires.

When the active component of the present invention is formulated into aninjection drug, it may take a form of an oil solution, an emulsion or anaqueous solution. Such liquid formulations may contain an emulsifier, astabilizer, etc. which are commonly employed.

Depending upon the manner of administration, these drugs may contain atleast 1% by weight, preferably from 5 to 50% by weight, of the activeingredient.

Further, the active ingredient of the present invention may beformulated into a suppository by a usual method.

Now, Test Examples will be given to show the drug effect-enhancingactivities of the compounds of the present invention for antitumoragents.

TEST EXAMPLE 1

MTT colorimetric assay performed in a 96-well plate was used for an invitro chemosensitivity test. The assay is dependent on the reduction ofMTT by the mitochondrial dehydrogenase of viable cells to a blueformazan product which can be measured spectrophotometrically. Equalnumbers of cells (2,000 for KB-3-1 and 5,000 for KB-C₂) were inoculatedinto each well with 0.18 ml of culture medium. After overnightincubation (37° C., 5% CO₂), 20 μl of vincristine solution and 0.5 μl ofsample solution were added and incubated for 4 days. Then, 50 μl of MTT(1.1 mg/ml PBS) was added to each well and incubated for further 4hours. The resulting formazan was dissolved with 100 μl of DMSO afteraspiration of the culture medium. Plates were placed on a plate shakerfor 5 minutes and read immediately at 570 nm. IC₅₀ (ng/ml) with a testedsample 10 μM is given in Table 1; and IC₅₀ of vincristine without asample was 5,000 ng/ml. MTT:3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide MEM:minimum essential medium

The test results are shown in Table 1.

    TABLE 1      Ar.sup.1 Z R.sup.1 R.sup.2 R.sup.3 IC.sub.50      ##STR4##      CO.sub.2      Et H     ##STR5##      Et  5      ##STR6##      CO.sub.2 Me H CH.sub.3 Me 120      ##STR7##      ##STR8##      H CH.sub.3      ##STR9##      30      ##STR10##      ##STR11##      H CH.sub.3      ##STR12##      12      ##STR13##      CO.sub.2      Me H     ##STR14##      ##STR15##       6      ##STR16##      CO.sub.2      Me H     ##STR17##      ##STR18##      27      ##STR19##      ##STR20##      H CH.sub.3      ##STR21##      15      ##STR22##      ##STR23##      H CH.sub.3      ##STR24##      <5      ##STR25##      ##STR26##      H CH.sub.3      ##STR27##      <5      ##STR28##      CO.sub.2      CH.sub.3 H CH.sub.3     ##STR29##      13      ##STR30##      ##STR31##      H CH.sub.3      ##STR32##       5      ##STR33##      ##STR34##      H CH.sub.3      ##STR35##      19      ##STR36##      ##STR37##      H CH.sub.3      ##STR38##       6      ##STR39##      ##STR40##      H CH.sub.3      ##STR41##       6      ##STR42##      ##STR43##      H CH.sub.3      ##STR44##       6      ##STR45##      ##STR46##      H CH.sub.3 CH.sub.3 <5      ##STR47##      ##STR48##      H CH.sub.3      ##STR49##       6      ##STR50##      ##STR51##      H CH.sub.3      ##STR52##      <5      ##STR53##      ##STR54##      H CH.sub.3      ##STR55##       7      ##STR56##      CO.sub.2      CH.sub.3 H CH.sub.3     ##STR57##      14      ##STR58##      ##STR59##      H CH.sub.3 CH.sub.3  7      ##STR60##      ##STR61##      H CH.sub.3      ##STR62##      60      ##STR63##      ##STR64##      H CH.sub.3      ##STR65##      10      ##STR66##      ##STR67##      H CH.sub.3      ##STR68##      21      ##STR69##      ##STR70##      H CH.sub.3      ##STR71##      <10      ##STR72##      ##STR73##      H CH.sub.3      ##STR74##      320      ##STR75##      ##STR76##      H CH.sub.3      ##STR77##      300      ##STR78##      ##STR79##      H CH.sub.3      ##STR80##      68      ##STR81##      ##STR82##      -- CH.sub.3      ##STR83##      <5      ##STR84##      ##STR85##      H CH.sub.3      ##STR86##      250      ##STR87##      ##STR88##      H CH.sub.3      ##STR89##      32      ##STR90##      ##STR91##      H CH.sub.3      ##STR92##      660      ##STR93##      ##STR94##      -- CH.sub.3      ##STR95##      52      ##STR96##      ##STR97##      H CH.sub.3      ##STR98##      32      ##STR99##      ##STR100##      H CH.sub.3      ##STR101##      210      ##STR102##      ##STR103##      -- CH.sub.3      ##STR104##      42      ##STR105##      ##STR106##      H CH.sub.3 Me 520      ##STR107##      ##STR108##      H CH.sub.3      ##STR109##      25      ##STR110##      ##STR111##      H CH.sub.3      ##STR112##      <10      ##STR113##      ##STR114##      H CH.sub.3      ##STR115##      <5      ##STR116##      ##STR117##      H CH.sub.3      ##STR118##      <10      ##STR119##      ##STR120##      H CH.sub.3      ##STR121##      <5      ##STR122##      ##STR123##      H CH.sub.3      ##STR124##      52      ##STR125##      ##STR126##      H CH.sub.3      ##STR127##      260      ##STR128##      ##STR129##      H CH.sub.3      ##STR130##       5      ##STR131##      ##STR132##      H CH.sub.3      ##STR133##       5      ##STR134##      ##STR135##      H CH.sub.3      ##STR136##      <5      ##STR137##      ##STR138##      H CH.sub.3      ##STR139##      100      ##STR140##      ##STR141##      H CH.sub.3      ##STR142##      <5      ##STR143##      ##STR144##      H CH.sub.3      ##STR145##      500      ##STR146##      ##STR147##      H CH.sub.3      ##STR148##      <5      ##STR149##      ##STR150##      H CH.sub.3      ##STR151##      200      ##STR152##      ##STR153##      H CH.sub.3      ##STR154##      260      ##STR155##      ##STR156##      H CH.sub.3      ##STR157##      35      ##STR158##      ##STR159##      H CH.sub.3      ##STR160##      410      ##STR161##      ##STR162##      H CH.sub.3      ##STR163##      560      ##STR164##      ##STR165##      H CH.sub.3      ##STR166##      300      ##STR167##      ##STR168##      H CH.sub.3      ##STR169##      <10      ##STR170##      ##STR171##      H CH.sub.3      ##STR172##      120      ##STR173##      ##STR174##      H CH.sub.3      ##STR175##       9      ##STR176##      ##STR177##      H CH.sub.3      ##STR178##      41      ##STR179##      ##STR180##      -- CH.sub.3      ##STR181##      <5      ##STR182##      ##STR183##      H CH.sub.3      ##STR184##      500      ##STR185##      ##STR186##      H CH.sub.3      ##STR187##       9      ##STR188##      ##STR189##      H CH.sub.3      ##STR190##       6      ##STR191##      ##STR192##      H CH.sub.3      ##STR193##      50      ##STR194##      ##STR195##      H CH.sub.3      ##STR196##      900      ##STR197##      ##STR198##      H CH.sub.3      ##STR199##       6      ##STR200##      ##STR201##      H CH.sub.3      ##STR202##      <5      ##STR203##      ##STR204##      H CH.sub.3      ##STR205##       8      ##STR206##      ##STR207##      H CH.sub.3      ##STR208##      200      ##STR209##      ##STR210##      H CH.sub.3      ##STR211##      220      ##STR212##      CO.sub.2      Me H CH.sub.3     ##STR213##      38      ##STR214##      ##STR215##      H CH.sub.3      ##STR216##      130      ##STR217##      ##STR218##      H CH.sub.3      ##STR219##      500      ##STR220##      ##STR221##      H CH.sub.3      ##STR222##      12      ##STR223##      ##STR224##      H CH.sub.3      ##STR225##       5      ##STR226##      ##STR227##      H CH.sub.3      ##STR228##      190      ##STR229##      ##STR230##      H CH.sub.3      ##STR231##       5      ##STR232##      ##STR233##      H CH.sub.3      ##STR234##      280      ##STR235##      ##STR236##      H CH.sub.3      ##STR237##       6      ##STR238##      ##STR239##      H CH.sub.3      ##STR240##      13      ##STR241##      ##STR242##      H CH.sub.3      ##STR243##      10      ##STR244##      ##STR245##      H CH.sub.3      ##STR246##      170      ##STR247##      ##STR248##      H CH.sub.3      ##STR249##      20      ##STR250##      ##STR251##      H CH.sub.3      ##STR252##       6      ##STR253##      ##STR254##      H CH.sub.3      ##STR255##      200      ##STR256##      ##STR257##      H CH.sub.3      ##STR258##      40      ##STR259##      ##STR260##      H CH.sub.3      ##STR261##      28      ##STR262##      ##STR263##      H CH.sub.3      ##STR264##      35      ##STR265##      ##STR266##      H CH.sub.3      ##STR267##       6      ##STR268##      ##STR269##      H CH.sub.3      ##STR270##       7      ##STR271##      ##STR272##      ##STR273##      CH.sub.3      ##STR274##      <5      ##STR275##      ##STR276##      H CH.sub.3      ##STR277##      28      ##STR278##      ##STR279##      H CH.sub.3      ##STR280##       5      ##STR281##      ##STR282##      -- CH.sub.3      ##STR283##      <10      ##STR284##      ##STR285##      H CH.sub.3      ##STR286##       8      ##STR287##      ##STR288##      H CH.sub.3      ##STR289##      500      ##STR290##      ##STR291##      H CH.sub.3      ##STR292##       8      ##STR293##      ##STR294##      -- CH.sub.3      ##STR295##      540      ##STR296##      CO.sub.2      Me -- CH.sub.3     ##STR297##      54      ##STR298##      CO.sub.2      Me -- CH.sub.3     ##STR299##      14      ##STR300##      ##STR301##      -- CH.sub.3      ##STR302##       6      ##STR303##      CO.sub.2      Me -- CH.sub.3     ##STR304##      67

TEST EXAMPLE 2

300 human carcinoma KB-3-1 cells or multidrug resistant KB-Cl cells wereincubated in a glucose culture medium for 16 hours. A solution ofvincristine alone, or of vincristine and a sample compound in DMSO, wasadded thereto, and the cells were incubated at 37° C. for further days.Colonies were stained with a 0.5% methylene blue in 50% ethanol, andcounted. The concentration of vincristine inhibiting the formation ofthe cell colonies 50% (IC₅₀) was investigated in the presence or absenceof the sample. Each value represents relative resistance to vincristinethat was determined by dividing the IC₅₀ of KB-3-1 for vincristine inthe presence of a sample or the IC₅₀ of KB-Cl for vincristine in theabsence of the sample by the IC₅₀ of KB-3-1 for vincristine in theabsence of the sample

The test results are shown in Table 2.

                                      TABLE 2                                     __________________________________________________________________________    Activities for enhancing drug effects of vincristine against                  parent strain (KB-3-1) and its drug resistant strain (KB-Cl)                   ##STR305##                                                                   Compound                                 Concentration                         ##STR306##                                                                          ##STR307##                                                                             ##STR308##                                                                                ##STR309##                                                                                  ##STR310##                                                                            ##STR311##                                                                        ##STR312##              __________________________________________________________________________          No administration                   0      1   1200                     (1)   m-Nitrophenyl                                                                          CH.sub.2 CH.sub.2 N(CH.sub.3)CH.sub.2 Ph                                                  OCH.sub.2 C(CH.sub.3).sub.2 CH.sub.2 O                                                      10      0.2 34                       (2)   m-Nitrophenyl                                                                          2-(4-diphenylmethyl-                                                                      OCH(CH.sub.3)CH.sub.2 CH(CH.sub.3)O                                                         10      0.1 0.5                                     1-piperazinyl)ethyl                                            (3)   m-Nitrophenyl                                                                          CH.sub.2 CH.sub.2 N(CH.sub. 3)CH.sub.2 Ph                                                 R.sup.4 : CH.sub.3 O                                                                        10      0.2 14                                                  R.sup.5 : CH.sub.3 O                               (4)   m-Nitrophenyl                                                                          CH.sub.3    R.sup.4 : PhCH.sub.2 N(CH.sub.3)(CH.sub.2).sub.                               3 O           10      0.1 18                                                  R.sup.5 : CH.sub.3 O                               (5)   m-Nitrophenyl                                                                          CH.sub.2 CH.sub.2 N(CH.sub.3)CH.sub.2 Ph                                                  R.sup.4 : (CH.sub.3).sub.2 N                                                                10      0.1 0.7                                                 R.sup.5 : C.sub.2 H.sub.5 O                        (6)   m-Chlorophenyl                                                                         CH.sub.2 CH.sub.2 N(CH.sub.3)CH.sub.2 Ph                                                  N(CH.sub.3)CH.sub.2 CH.sub.2 N(CH.sub.3)                                                    10      0.1 1.0                      __________________________________________________________________________     (In the Table, Ph means phenyl.)                                         

Now, two typical methods for oxidizing 1,4-dihydropyridine derivativesto the corresponding pyridine derivatives, will be described in detail.

OXIDATION EXAMPLE 1

Preparation of5-(cis-4,6-dimethyl-1,3,2-dioxaphosphorinan-2-yl),2,6-dimethyl-4-(3-nitrophenyl)-3-pyridinecarboxylicacid 4-diphenylmethyl-1-piperadinoethylester p-oxide

10 ml of 36% nitric acid was added to 1.4 g of5-(cis-4,6-dimethyl-1,3,2-dioxaphosphorinan-2-yl)-1,4-dihydro-2,6-dimethyl-4-(3-nitrophenyl)-3-pyridinecarboxylicacid 4-diphenylmethyl-1-piperadinoethylester p-oxide dihydrochloride,and the mixture was stirred at 50° C. for 10 minutes.

After cooling, the mixture was neutralized with a saturated sodiumhydrogencarbonate aqueous solution and extracted with chloroform. Theextract was dried over anhydrous sodium sulfate. Then, the solvent wasdistilled off under reduced pressure, and the residue was subjected tosilica gel chromatography (developing solvent: ethyl acetate Rf=0.5) toobtain 1.2 g (yield 95%) of the above identified compound as yellow oilysubstance.

The analytical values are shown below.

NMR δ(ppm) CDCl₃ 1.02(3H,dd,J=1.6 Hz,6.2 Hz), 1.16(3H,dd,J=1.6 Hz,6.2Hz), 1.12 (1H,m), 1.57(1H,m), 2.20-2.50(10H,m), 2.59(3H,s), 2.99(3H,s),3.90-4.10(2H,m), 4.19(1H,s), 4.60-4.80(2H,m), 7.17 (2H, t,J=7.4 Hz ),

7.26(4H,dd,J=7.4 Hz,7.0 Hz), 7.39(4H,d,J=7.0 Hz), 7.53 (1H,m),7.59(1H,m), 8.15(1H,m), 8.25(1H,m) MS (FAB) 699 (50%, M30 1), 167 (100%)

OXIDATION EXAMPLE 2 Preparation of5-(5,5-.dimethyl-1,3,2-dioxaphosphorinan-2-yl)-2,6-dimethyl-4-(3-nitrophenyl)-3-pyridinecarboxylicacid 2-N-phenyl)aminoethylester p-oxide

5.6 g of5-(5,5-dimethyl-1,3,2-dioxaphosphorinan-2-yl)-1,4-dihydro-2,6-dimethyl-4-(3-nitrophenyl)-3-pyridinecarboxylicacid 2-(N-phenyl)aminoethylester poxide was dissolved in 20 ml of aceticacid. After adding 2 g of chromium trioxide, the mixture was heated at100° C. for 30 minutes.

After cooling, the solvent was distilled off under reduced pressure. Tothe residue, a saturated sodium hydorgencarbonate aqueous solution wasadded for neutralization, and the mixture was extracted with 100 ml ofethyl acetate. The extract was dried over anhydrous sodium sulfate, andthe solvent was distilled off under reduced pressure. To the residue, 10ml of methanol, 10 ml of ethanol and 2 g of p-toluene sulfonic acid, andthe mixture was refluxed under heating for 7 hours. The solvent wasdistilled off under reduced pressure. Then, a saturated sodiumhydrogencarbonate aqueous solution was added, and the mixture wasextracted with 100 ml of ethyl acetate. The extract was dried overanhydrous sodium sulfate. Then, solvent was distilled off under reducedpressure, and the residue was subjected to silica gel chromatography(developing solvent: ethyl acetate Rf=0.6) to obtain 4.2 g of theabove-identified compound (yield: 79%, melting point: 105°-106° C.) asyellow crystals.

The analytical values are shown below.

NMR δ(ppm) CDCl₃ 0.75(3H,s), 1.09(3H,s), 2.60(3H,s), 2.89(3H,s),3.0-3.70(6H,m), 4.14(2H,t,J=6Hz), 6.30-8.30(9H,m)

Now, examples for the drugs containing the compounds of the presentinvention will be presented.

EXAMPLES 1

Hard capsules for oral administration

25 g of hydrochloride of the compound (2), 5 g of adriamycin and 7.5 gof polyoxyethylene castor oil were dissolved in methanol. Then, 25 g ofsilicic anhydride was mixed thereto. Methanol was distilled off, andthen 5 g of calcium carboxymethyl cellulose, 5 g of corn starch, 7.5 gof hydroxypropyl cellulose and 20 g of fine crystal cellulose were mixedthereto. Then, 30 ml of water was added, and the mixture was kneaded andgranulated. The product was granulated by a granulation machine equippedwith a screen of No. 24 mesh (B.S.). Granules were dried to a watercontent of not higher than 5% and sieved with a screen of No. 16 mesh(B.S.). Then, the particles were filled in capsules by a capsule fillingmachine in an amount of 200 mg per capsule.

EXAMPLE 2

Soft capsules for oral administration

30 g of hydrochloride of compound (2), 7.5 g of adriamycin and 130 g ofpolyethylene glycol (Macrogol 400) were mixed to obtain a uniformsolution.

Separately, a gelatin solution comprising 93 g of gelatin, 19 g ofglycerol, 10 g of D-sorbitol, 0.4 g of ethyl p-oxybenzoate, 0.2 g ofpropyl p-oxybenzoate and 0.4 g of titanium oxide, was prepared. By usingthis as a capsule coating agent, soft capsules each containing 190 mg ofthe content were prepared by a manual flat plate punching method.

EXAMPLE 3

Soft capsules for oral administration.

40 g of hydrochloride of compound (2), 4 g of adriamycin and 120 g ofpolyethylene glycol (Macrogol 400) were mixed to obtain a uniformsolution.

Separately, a gelatin solution comprising 90 g of gelatin, 16 g ofglycerol, 8 g of D-sorbitol, 0.35 g of ethyl p-oxybenzoate, 0.2 g ofpropyl p-oxybenzoate and 0.3 g of titanium oxide, was prepared. By usingthis as a capsule coating agent, soft capsules each containing 180 mg ofthe content were prepared by a manual flat plate punching method.

EXAMPLE 4

Injection drug

1 g of hydrochloride of compound (2), 1 g of adriamycin, a suitableamount of peanut oil and 1 g of benzyl alcohol were mixed, and the totalamount was brought to 100 ml by using peanut oil. The solution thusobtained was put into ampules in an amount of 1 ml under an asepticcondition and the ampules were closed.

EXAMPLE 5

Injection drug

1 g of hydrochloride of compound (2), 1 g of adriamycin, 5.0 g ofhydrogenated castor oil polyoxyethylene (60 mol) ether (Nikkol HCO 60,tradename), 20 g of propylene glycol, 10 g of glycerol and 5.0 g ofethyl alcohol were mixed, and 100 ml of distilled water was addedthereto. The mixture was stirred to obtain a solution. The solution wasput into ampules in an amount of 2.0 ml each under an aseptic condition,and the ampules were then closed.

EXAMPLE 6

Injection drug

1 g of hydrochloride of compound (2), 1 g of adriamycin, 5.0 g ofhydrogenated castor oil polyoxyethylene (60 mol) ether (Nikkol HCO 60,tradename), 20 g of propylene glycol, 10 g of glycerol and 5.0 g ofethyl alcohol were mixed, and 100 ml of distilled water was addedthereto. The mixture was stirred to obtain a solution. This solution wasput into ampules in an amount of 2.0 ml each under an aseptic condition,and the ampules were closed.

EXAMPLE 7

Hard capsules for oral administration.

25 g of hydrochloride of compound (2), 5 g of vincristine and 7.5 g ofpolyoxyethylene castor oil were dissolved in methanol. Then, 25 g ofsilicic anhydride was added thereto, methanol was evaporated, and 5 g ofcalcium carboxymethyl cellulose, 5 g of corn starch, 7.5 g ofhydroxypropyl cellulose and 20 g of fine crystalline cellulose weremixed, and 30 ml of water was added thereto. The mixture was kneaded andgranulated. This product was granulated by a granulator with a screen ofNo. 24 mesh (B.S.). Granules thus obtaines were dried to a water contentof not higher 5% and then sieved with a screen with No. 16 mesh (B.S.).

Then, the particles thus obtained were filled into capsules by a capsulefilling machine in an amount of 200 mg per capsule.

EXAMPLE 8

Soft capsules for oral administration

30 g of hydrochloride of compound (2), 7.5 of vincristine and 130 g ofpolyethylene glycol (Macrogol 400) were mixed to obtain a uniformsolution.

Separately, a gelatin solution comprising 93 g of gelatin, 19 g ofglycerol, 10 g of D-sorbitol, 0.4 g of ethyl p-oxybenzoate, 0.2 g ofpropyl p-oxybenzoate and 0.4 g of titanium oxide, was prepared. By usingthis as a capsule coating agent, soft capsules containing 190 mg of thecontent were prepared by a manual flat plate punching method.

EXAMPLE 9

Soft capsules for oral administration

40 g of hydrochloride of compound (2), 4 g of vincristine and 120 g ofpolyethylene glycol (Macrogol 400) were mixed to obtain a uniformsolution.

Separately, a gelatin solution comprising 90 g of gelatin, 16 g ofglycerol, 8 g of D-sorbitol, 0.35 g of ethyl p-oxybenzoate, 0.2 g ofpropyl p-oxybenzoate and 0.3 g of titanium oxide, was prepared. By usingthis as a capsule coating agent, soft capsules containing 180 mg of thecontent were prepared by a manual flat plate punching method.

EXAMPLE 10

Injection drug

1 g of hydrochloride of compound (2), 1 g of vincristine, a suitableamount of peanut oil and 1 g of benzyl alcohol were mixed, and the totalamount was brought to 100 cc by using peanut oil. This solution was putinto ampules in an amount of 1 ml per ampule under an aseptic condition,and the ampules were closed.

EXAMPLE 11

Injection drug

1 g of hydrochloride of compound (2), 1 g of vincristine, 5.0 g ofhydrogenated castor oil polyoxyethylene (60 mol) ether (Nikkol HCO 60,tradename), 20 g of propylene glycol, 10 g of glycerol and 5.0 g ofethyl alcohol were mixed, and 100 ml of distilled water was addedthereto. The mixture was stirred to obtain a solution. This solution wasput into ampules in an amount of 2.0 ml per ampule under an asepticcondition, and the ampules were closed.

EXAMPLE 12

Injection drug

1 g of hydrochloride of compound (2), 1 g of vincristine, 5.0 g ofhydrogenated castor oil polyoxyethylene (60 mol) ether (Nikkol HCO 60,tradename), 20 g of propylene glycol, 10 g of glycerol and 5.0 g ofethyl alcohol were mixed, and 100 ml of distilled water was addedthereto. The mixture was stirred to obtain a solution. This solution wasput into ampules in an amount of 2.0 ml per ampule under an asepticcondition, and the ampules were closed.

Now, Examples will be given to illustrate the preparation of a drug inwhich the compound of the present invention is administered separatelyfrom an antitumor drug.

EXAMPLE 13

Tablets

    ______________________________________                                        Composition (1,000 tablets)                                                   ______________________________________                                        Hydrochloride of the compound                                                                          55.0   (g)                                           of Example (2)                                                                Lactose                  190.0                                                Corn starch              75.0                                                 Fine crystalline cellulose                                                                             25.0                                                 Methyl cellulose         3.0                                                  Magnesium stearate       2.0                                                                           350.0  (g)                                           ______________________________________                                    

The above components were charged into a V-type mixer and uniformlymixed. This powder mixture was directly tabletted to obtain tabletshaving a weight of 350 mg per tablet.

EXAMPLE 14

Capsules

    ______________________________________                                        Composition (1,000 capsules)                                                  ______________________________________                                        Hydrochloride of the compound                                                                          55     (g)                                           of Example (2)                                                                Corn starch              145                                                  Fine crystalline cellulose                                                                             145                                                  Magnesium stearate       5                                                                             350    (g)                                           ______________________________________                                    

The above compositions were charged into a V-type mixer and uniformlymixed. This powder mixture was filled in hard capsules. The content percapsule was 350 mg.

EXAMPLE 15

Syrups

    ______________________________________                                        Composition (2% solution)                                                     ______________________________________                                        Hydrochloride of the compound                                                                       2.0 (g)                                                 of Example (2)                                                                Sucrose               30.0                                                    Glycerol              5.0                                                     Flavor                0.1                                                     96% Ethanol           10.0                                                    Methyl p-oxybenzoate  0.03                                                    ______________________________________                                    

Distilled water to bring the total amount to 100.0 g

Sucrose and hydrochloride of the compound of Example 1 were dissolved in60 g of warm water and then cooled. Thereafter, a flavor solutiondissolved in glycerol and ethanol was added thereto. Then, water wasadded to this mixture to bring the total amount to 100.0 g.

EXAMPLE 16

Powder

    ______________________________________                                        Hydrochloride of the compound                                                                          5.0    (g)                                           of Example (2)                                                                Lactose                  84.0                                                 Fine crystalline cellulose                                                                             10.0                                                 Methyl cellulose         1.0                                                                           100.0  (g)                                           ______________________________________                                    

The above components were charged into a V-type mixer and uniformlymixed.

EXAMPLE 17

Injection drug

1 g of hydrochloride of compound (2), a suitable amount of peanut oiland 1 g of benzyl alcohol were mixed, and the total amount was broughtto 100 cc by using peanut oil. This solution was put into ampules in anamount of 1 ml per ampule under an aseptic condition, and the ampuleswere closed.

We claim:
 1. A pyridine compound which is 2-ethyl2,6-dimethyl-5-(4,6-dimethyl-2-oxo-1,3,2-dioxaphosphorinan-2-yl)-4-(3-nitrophenyl)-3-pyridinecarboxylate.